[lkml]   [2006]   [Dec]   [10]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
SubjectRe: strncpy optimalisation? (lib/string.c)
On Sun, 2006-12-10 at 22:39 +0100, Folkert van Heusden wrote:
> > > Original code completely pads the destination with zeroes,
> > > while yours only adds the last zero. Your code does what
> > > strncpy() is said to do, but maybe there's a particular
> > > reason for it to behave differently in the kernel
> > No, the kernel's strncpy() behaves the same as the one in libc. Run
> > "man strncpy" if you don't believe me.
> > In the common case where you just want to copy a string and avoid
> > overflow use strlcpy() instead
> Oops you're right! Maybe someone should take a look if the strncpy's
> should be replaced by strlcpy's then because it is (ought to be) faster.

The last time some folks did this (quite automatically) ended in newly
introduced bugs leaking old/stale data from kernel top user space. Alan
Cox went over it (again) and fixed those broken "optimizations".

So whoever wants to do this, look for such issues too.

Firmix Software GmbH
mobil: +43 664 4416156 fax: +43 1 7890849-55
Embedded Linux Development and Services

To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to
More majordomo info at
Please read the FAQ at

 \ /
  Last update: 2006-12-11 00:33    [W:0.037 / U:3.048 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site